The rapid expansion in the use of the Internet has resulted in a demand for high speed communications links and devices, including optical links and devices. Optical links using fiber optics have many advantages compared to electrical links: large bandwidth, high noise immunity, reduced power dissipation and minimal crosstalk. Optoelectronic integrated circuits made of silicon are highly desirable since they could be fabricated in the same foundries used to make VLSI integrated circuits. Optical devices integrated with their associated electronic circuits can eliminate the need for more expensive hybrid optoelectronic circuits. Optical devices built using a standard. CMOS process are very desirable for many reasons: high yields, low fabrication costs and continuous process improvements.